This invention relates to an improved tape closure for sealed containers.
For many years secondary closures have been applied to lidded, stoppered, or capped containers by wrapping a strip of adhesive-coated shrinkable film around the container at the line of closure, thereafter heating the film to shrink the tape firmly and snugly in place; see, e.g., U.S. Pat. No. 3,405,833. It is also known to incorporate in the closure a tear strip which is positioned between the inner aspect of the tape and the container, along the line of closure, to facilitate opening; see, e.g., U.S. Pat. No. 3,873,018. The tear strip, which extends to the outer side of the closure, provides a convenient means for the user to rupture the tape seal and thereafter open the primary closure on the container.
As applied to wine bottles, for example, it is important that the secondary tape closure be aesthetically appealing both before and after opening. The closure should conform smoothly to both the neck of the bottle and that portion of the cork or cap which is adjacent the line of primary closure. Likewise, after the tape closure is ruptured by means of a tear strip, the line along which the tape has been severed should be sharp and even, enhancing the visual appeal of the opened container to the user.
Prior to the present invention, a wide variety of heat-shrinkable polymeric films have been employed as secondary tape closures, and while many have proved functionally satisfactory, none has been considered adequate from an aesthetic point of view. For example, either heat-shrinkable oriented polyethylene terephthalate film or unplasticized polyvinyl chloride film can be shrunk in place to provide an extremely attractive appearance before the closure is opened; when a tear strip is used to open seals made with these films, however, the line of rupture is irregular and unattractive, making such closures inherently unsatisfactory from the consumer's -- and hence from the manufacturer's -- point of view. On the other hand, films made of either atactic polystyrene or isotactic polypropylene, which tear along a straight line when employed in a closure, lack the ability to shrink so as to conform smoothly to the contours of the original bottle; the irregular appearance detracts from the aesthetic appeal of the product and tends to discourage its purchase by consumers.
Prior to the present invention, then, it is believed that there has not existed a tape closure for wine bottles and the like possessing aesthetic appeal both before and after opening of the bottle.